Many planar composite panels are formed with a number of discrete stiffener members or "stringers" affixed to, or integrally formed with, one side of the panel. Frequently, the stringers are formed of the same composite materials as the remainder of the panel. In any event, the stringers are constructed in such a manner and positioned to carry a high percentage of the axial loading that is applied to the panel when the panel is in use.
The use of discretely stiffened composite panels has become more widespread as the structural integrity of such panels has improved. One area in which the use of such panels is expanding is the jet aircraft field, particularly the commercial jet transport field. One impediment to the continued expansion of the use of stiffened composite panels in jet transport aircraft has been the difficulty associated with the end splicing of such panels in a structurally acceptable, yet inexpensive, manner.
In the past, it was thought that end-to-end splicing of discretely stiffened panels required the use of complex fastening devices. The fastening devices were complex because they were designed to splice the stiffener members, e.g., stringers, as well as the remainder of the panels. It was assumed that stiffener splicing was required so that the axial load bearing properties of the panels remained substantially unaffected across the splice section.
This invention provides discretely stiffened composite panels that can be spliced in a structurally acceptable manner with uncomplicated splicing devices. This invention further provides discretely stiffened composite panels wherein the composite material layers used to form the panels are sized and oriented to enhance the fast, cost effective, automatic fabrication of the panels.